MRI and Echocardiographic Measures of Infarct Scar Size (ISS) and Left Regional and Global Ventricular Function [ Time Frame: Measured over the 6-month follow-up period and at Month 18 follow-up ] [ Designated as safety issue: No ]

Cardiac Computed Tomography Measures of ISS, Left Ventricular Ejection Fraction, and End Diastolic and End Systolic Volumes [ Time Frame: Measured over the 6-month follow-up period and at Month 18 follow-up ] [ Designated as safety issue: No ]

New York Heart Association (NYHA) Functional Class [ Time Frame: Measured over the 6-month follow-up period and at Month 18 follow-up ] [ Designated as safety issue: No ]

Minnesota Living With Heart Failure (MLHF) Questionnaire [ Time Frame: Measured over the 6-month follow-up period and at Month 18 follow-up ] [ Designated as safety issue: No ]

Incidence of the Major Adverse Cardiac Events (MACE) Endpoint, Defined as the Composite Incidence of (1) Death, (2) Hospitalization for Heart Failure, or (3) Non-fatal Recurrent Heart Attack [ Time Frame: Measured over the 6-month follow-up period and at Month 18 follow-up ] [ Designated as safety issue: No ]

Heart attacks are a leading cause of death in both men and women in the United States. When a person has a heart attack, blood is unable to reach a certain area of the heart, and if the blood supply is not re-established quickly, that area of the heart can suffer permanent damage. While recovery from a heart attack can be managed through medications and lifestyle changes, these treatments can not reverse the original damage to the heart. Current research is focusing on the development of cell-based therapies using stem cells to repair organs that have been irreversibly damaged by disease. A specific form of stem cells, called adult mesenchymal stem cells (MSCs), has shown promise for heart repair. This study will evaluate the safety and effectiveness of injecting MSCs into the heart to repair and restore heart function in people who have had a heart attack and who are having heart surgery for coronary artery bypass grafting (CABG).

Detailed Description

Participation in this study will last 18 months. Potential participants will undergo initial screening 5 to 7 weeks prior to CABG surgery. Screening will include a physical exam, blood draw, pregnancy test, questions about medical history, current medications, and alcohol or drug use, an electrocardiogram (ECG), magnetic resonance imaging (MRI) of the heart, questionnaires, an echocardiogram and a computed tomography (CT) scan. Eligible participants will then undergo two baseline visits within 6 weeks of their scheduled surgery. Baseline Visit 1 will consist of vital sign measurements, a bone marrow aspiration to obtain MSCs and a blood draw for a biomarker test. Baseline Visit 2 will include treadmill test, 6-minute walk test, pulmonary function (FEV1) study and a 48 Hour Ambulatory ECG. After the second baseline visit, participants will be assigned randomly to receive either MSCs or placebo after surgery.

On the day of surgery, once all of the bypass grafts have been placed, a high or low dose of MSCs or placebo will be injected into a damaged area of the heart that did not receive a bypass graft. After receiving the injections, participants will remain in the hospital for up to 7 days. During this stay, participants will undergo a daily blood draw, urine test, ECG, and ambulatory ECG monitoring for the first 96 hours after surgery.

Upon being discharged, participants will return for monthly visits for 6 months and for follow-up visits 12 and 18 months after surgery. These visits will repeat most initial screening and baseline tests. There will be one additional visit 14 days after surgery, which will include questions about side effects, a physical exam, and a 48-hour ambulatory ECG.

Participants will receive between 10 and 20 intramyocardial injections of 2 million MSCs per 0.25-0.5 cubic centimeter (cc) for a total of 2 x 107 cells. The injections will be administered following completion of CABG surgery.

Participants will receive between 10 and 20 intramyocardial injections of 20 million MSCs per 0.25-0.5 cc for a total of 2 x 108 cells. The injections will be administered following completion of CABG surgery.